Posts Tagged "black carbon"

The Question of Black Carbon

Posted by on Oct 15, 2015 in All Posts, Featured Posts, Science | 0 comments

The Question of Black Carbon

Spread the News:ShareBlack carbon has only recently emerged as a known major contributor to climate change, especially for the Arctic. Formed by the incomplete combustion of fossil fuels, biofuels, and biomass, black carbon absorbs light more strongly than any other particulate matter, especially when deposited onto glaciers and snow cover. Here, it lowers their reflectivity, thereby absorbing atmospheric heat and resulting in earlier spring melt and higher temperatures. New research, published in Atmospheric Chemistry and Physics, is attempting to address research gaps in this new but significant climate agent by quantifying and analyzing black carbon concentration and deposition in Svalbard, the major archipelago north of Norway. The study, focusing on black carbon on the Holtedahlfonna glacier in Svalbard between 1700 and 2004, found significant rises in black carbon concentration from the 1970s until 2004 , with unprecedented levels in the 1990s.  Importantly, the study concludes that the increase in black carbon concentration “cannot be simply explained by changes in the snow accumulation rate at the glacier,” or simply by glacial melt and shrinkage in Svalbard. This indicates that black carbon was instead deposited in increasing quantities during this time period. The study raises some puzzling differences between black carbon concentrations and deposition in Svalbard and between previous data from other Arctic regions. While Svalbard’s black carbon values increased rapidly from a low point in 1970 until 2004, reaching a high in the 1990s, black carbon analyzed in Greenland ice cores indicated generally decreasing atmospheric black carbon concentrations since 1989 in the Arctic. This difference is likely at least partly explained by differences in the specific methodologies used in the studies, such as the operational definition of black carbon that determined which size particles were included in the study. The Svalbard study collected its data by filtering the inner part of a 125 m deep ice core from the Holtedahlfonna glacier through a quartz fiber filter. The filtrate was analyzed using a thermal-optical method, while previous comparable studies used an SP2 (Single Particle Soot Photometer) method. The different methodologies used between studies makes it hard to assess the validity of the studies’ findings. Indeed, previous studies on black carbon on Himalayan and European ice cores have repeatedly shown different and contracting trends when measured with different analytical methods, even when studies examined the same glaciers. This indicates a significant need for more and improved research on black carbon research in the Arctic. Black carbon concentrations, as the study reveals, are immensely complicated and depend on a variety of factors, such as air concentration of black carbon, the amount of precipitation, local wind drift patterns post-deposition, sublimation, and melt. Black carbon concentration can also be affected by sudden changes in snow and ice accumulation, or seasonal melt. These factors make it difficult for scientists to collect faithful data of black carbon concentration over time. However, black carbon data in the Arctic is incredibly important: in the Arctic, black carbon is a more important warming agent than greenhouse gases. Its levels are intensely impacted from local and regional emission sources near Svalbard, such as forest and wild fires and flaring at gas wells in Russia, impacts that are difficult to accurately quantify, the researcher state. While this study sheds light on recent trends of black carbon levels in Svalbard, it raises some key questions about the particle’s measurement, suggesting a need for further development of accurate black carbon measurement techniques and for further research on the role black carbon plays in Arctic warming. Spread the...

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Roundup: Snowmaking Guns, Antarctic Ice, and Black Carbon

Posted by on Jun 22, 2015 in All Posts, Featured Posts, News, Roundup, Science | 0 comments

Roundup: Snowmaking Guns, Antarctic Ice, and Black Carbon

Spread the News:ShareSki Resort’s New Snowmaking Guns  Describing a major ski resort in British Columbia, Canada: “De Jong says that after commercial operations end in July, four snowmaking guns and other infrastructure will be installed. It is expected to be used beginning in October. ‘If the pilot project is conclusive, this unique project will become a significant addition to Whistler Blackcomb’s list of adaptations to ensure long-term resilience against climate change,’ he said.” Read here for more info. Sudden and Rapid Ice Loss Discovered in Antarctica “Several massive glaciers in the southern Antarctic Peninsula suddenly started to crumble in 2009, a new study reports today (May 21) in the journal Science. ‘Out of the blue, it’s become the second most important contributor to sea level rise in Antarctica,’ said lead study author Bert Wouters, a remote sensing expert and Marie Curie Fellow at the University of Bristol in the United Kingdom.” Read here for more info. Study uses ice cores to estimate biomass burnings’ contributions to black carbon “We analyzed refractory black carbon (rBC) in an ice core spanning 1875–2000 AD from Mt. Muztagh Ata, the Eastern Pamirs [of western China], using a Single Particle Soot Photometer (SP2)…. Mean rBC concentrations increased four-fold since the mid-1970s and reached maximum values at end of the 1980s. The observed decrease of the rBC concentrations during the 1990s was likely driven by the economic recession of former USSR countries in Central Asia. Levoglucosan concentrations showed a similar temporal trend to rBC concentrations, exhibiting a large increase around 1980 AD followed by a decrease in the 1990s that was likely due to a decrease in energy-related biomass combustion. The time evolution of levoglucosan/rBC ratios indicated stronger emissions from open fires during the 1940s–1950s, while the increase in rBC during the 1980s–1990s was caused from an increase in energy-related combustion of biomass and fossil fuels.” Read here for more info. Spread the...

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Roundup: Bubbling Ice, Black Carbon, and Glacial Advance

Posted by on Jun 1, 2015 in All Posts, Featured Posts, News, Roundup, Science | 0 comments

Roundup: Bubbling Ice, Black Carbon, and Glacial Advance

Spread the News:ShareThe sound of glaciers A new article in the scientific journal Geophysical Research Letters, titled Unusually loud ambient noise in tidewater glacier fjords: A signal of ice melt, tracks glacial melt by recording the sounds of the glaciers bubbling underwater in glacial bays. Check out videos of the unique sounds below, and read the article here. http://glacierhub.org/wp-content/uploads/2015/06/grl52695-sup-0003-MovS3.mp4   http://glacierhub.org/wp-content/uploads/2015/06/grl52695-sup-0004-MovS4.mp4 “After decades of retreat, in the 1980s, many Karakoram glaciers suddenly ‘changed their mind.'” According to Kenneth Hewitt, a glaciologist at Wilfrid Laurier University, Waterloo, in Canada, ‘I began to see glacier thickening and advancing that I had not observed in the 35 years of field work before.’ Hewitt called it the ‘Karakoram anomaly,’ and climate-change skeptics made the most of it. Read the full story by Jane Qiu in Science. New Report on Black Carbon in the Peruvian Andes According to the study, tropical glacial melt is rapidly affecting water supplies and high concentrations of “light-absorbing particles on glacier surfaces” are part of the reason. Read the full report here.   Spread the...

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Photo Friday: Cryoconites and Glacier Tables

Posted by on May 29, 2015 in All Posts, Featured Posts, Images, Science | 0 comments

Photo Friday: Cryoconites and Glacier Tables

Spread the News:ShareHave you ever seen dark cavities on glaciers, which are also referred to as “cryoconites”? These holes, which can be meters deep,are created from debris on top of glaciers. Dark-colored debris, including soot, dust, and pollen, speed up the melting process of glacial ice as a consequence of their low reflectivity to incoming sunlight. In some cases, glacial surface debris can also form pits in the ice through chemical melting. Hence, most of the glacial thaw holes are filled with melt-water, which become home to cyanobacteria, fungi, and other microbes. However, some large solid debris, in particular boulders, will prevent the ice beneath from melting as surrounding ice, forming glacier tables. Here are some photographs of cryoconites and glacier tables. Learn more about glacial surface debris here.   Glacier Table ©2010 Florian Mair Glacier Thaw Hole Source: Galia & Yoav/Flickr Cryoconites Source: Sandwich/Flickr Glacier Thaw Hole Source: Andrew E. Russell/Flickr Spread the...

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Roundup: Black Carbon, Winds, and Supraglacial Lakes

Posted by on May 4, 2015 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: Black Carbon, Winds, and Supraglacial Lakes

Spread the News:ShareLight-absorbing Particles in Peru “Glaciers in the tropical Andes have been rapidly losing mass since the 1970s. In addition to the documented increase in temperature, increases in light-absorbing particles deposited on glaciers could be contributing to the observed glacier loss. Here we report on measurements of lightabsorbing particles sampled from glaciers during three surveys in the Cordillera Blanca Mountains in Peru.” Read more here. Winds on Glaciers “We investigate properties of the turbulent flow and sensible heat fluxes in the atmospheric surface layer of the high elevation tropical Zongo glacier (Bolivia) from data collected in the dry season from July to August 2007, with an eddy-covariance system and a 6-m mast for wind speed and temperature profiles. Focus is on the predominant downslope wind regime.” Read more here. Supraglacial Lakes in Central Karakoram Himalaya “This paper discusses the formation and variations of supraglacial lakes on the Baltoro glacier system in the Central Karakoram Himalaya during the last four decades. We mapped supraglacial lakes on the Baltoro Glacier from 1978 to 2014 using Landsat MSS, TM, ETM+ and LCDM images. Most of the glacial lakes were formed or expanded during the late 1970s to 2008. After 2008, the total number and the area of glacial lakes were found to be lesser compared to previous years.” Read more here.   Spread the...

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